Method and control apparatus for operating a marine vessel

ABSTRACT

A method for performing a sideway displacement of a marine vessel. The marine vessel includes a first and a second propulsion unit, a first and a second rudder respectively associated with the first and the second propulsion units, and a bow thruster. The first and the second propulsion units, the first and the second rudders and the bow thruster are operable via a single driver interface. The method includes the steps of; via the single driver interface operate the first and the second propulsion units and the bow thruster so as to provide a total thrust and set the rudder angles of the first and the second rudders, to thereby steer the displacement of the marine vessel during the sideway displacement.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Stage application ofPCT/EP2016/061775, filed May 25, 2016 and published on Nov. 30, 2017 asWO2017/202458.

TECHNICAL FIELD

The present invention relates to a method for performing a sidewaydisplacement of a marine vessel using a single driver interface and anarrangement in the form of a steering arrangement for executing themethod. The marine vessel comprises a bow thruster and a first and asecond propulsion unit. Each propulsion unit is associated with arudder, whereby the rudders are set as a function of a total thrust, tothereby steer the displacement of the marine vessel during the sidewaydisplacement.

BACKGROUND

Joystick steering of marine vessels has been significantly improved whenthe Inboard Performance System IPS was introduced. Dual counter rotatingpropellers provided with steerable pods enable an exact joysticksteering and docking as compared to traditional inboard shafts havingnon steerable propellers. IPS provides a marine vessel driver with anumber of advantages such as joystick docking, joystick driving dynamicpositioning system, autopilot capabilities, sportfish mode andinterceptor systems just to mention a few.

The US patent publication no. 2014/352595 A1 discloses a method forsteering a marine vessel using a first and a second propulsion unit. Themethod includes the steps of receiving a first signal from a leftcontrol lever and a second signal from a right control lever, anddependent on the relative size of these signals, activate a clock-wiseturning moment or a counter clock-wise turning movement. However, as newand improved technology progresses little efforts are put intotraditional technology. Little efforts are put into rudder controlduring maneuvering as new and improved propeller maneuvering providessuch great advantages.

An early attempt in providing an apparatus for steering a marine vesselusing a joystick was presented in the U.S. Pat. No. 4,691,659 A. Theship steering apparatus comprised a pair of rotation angle detectors fordetecting the rotation angles around two X and Y axes from the motion ofa joystick lever. Based on the movement of the joystick lever, a shipsteering command could be calculated. The calculated steering commandcould thereafter be used to command the marine vessel.

It has lately been found that there is a need for an improved marinevessel steering control during displacement of the marine vesselespecially when the marine vessel is joystick controlled. There is aneed for a method which provides a relatively low cost option to improvemarine vessel control during joystick maneuvering and especially formarine vessels having no steerable stern drives.

SUMMARY

An object of the invention is to provide a method for performing asideway displacement of a marine vessel, which method is easy toimplement in a marine vessel and at a relatively low cost. The object isachieved by a method according to claim 1. More precisely is the objectachieved by a method for performing a sideway displacement of a marinevessel, the marine vessel comprising a first and a second propulsionunit, a first and a second rudder respectively associated with the firstand the second propulsion units, and a bow thruster. The first and thesecond propulsion units, the first and the second rudders and the bowthruster are operable via a single driver interface. The methodcomprises via the single driver interface;

operate the first and the second propulsion units and the bow thrusterso as to provide a total thrust and, setting the rudder angles of thefirst and the second rudders, to thereby steer the displacement of themarine vessel during the sideway displacement.

By the provision of the above method for performing a sidewaydisplacement of a marine vessel, the method enables a marine vessel toperform a smooth sideway displacement which is assisted by both rudders.The method is specifically advantageous when applied in a marine vesselhaving twin fixed inboard propulsion units, i.e. marine vessels havingnon-steerable propellers, and especially for docking maneuverers. Themethod further integrates the operation of the first and the secondpropulsion unit, the transmissions of the first and the secondpropulsion unit, the bow thruster with the first and the second rudderinto a single control function via the single driver interface such as ajoystick. Further, the present invention also provides an inexpensivearrangement that can assist the driver to manoeuvre the marine vessel toturn and displace the marine vessel sideways e.g. during docking. Themethod enables the possibility to perform a sideway displacement withoutthe need of a stern thruster. The method and the arrangement enable asmooth and relatively precise operation of the marine vessel.

The method may comprise the step of setting a function between therudder angles and the level of thrust of at least the bow thruster. Justas a matter of example, the higher the thrust, the higher the rudderangles may be set. Preferably the rudders are however not exceeding 20°port or starboard. This enables the option of setting a proportional andlinear relation between the rudder angles and the level of thrust of thebow thruster together with the propulsion from the propulsion units ifdesired. The mentioned function may thus be a mapped function such as alinear function or a non-linear function.

According to an embodiment, the rudder angles may be set to 0-20° portor starboard. It has been found that the rudder angles should not exceed20° port or starboard as this may affect the balancing of the marinevessel during the sideway displacement in a negative manner.

The method may comprise the step of setting the rudder angles of thefirst and the second rudders as a function of the total thrust. Bysetting the rudder angles as a function of the total thrust, the singledriver interface will effectively operate as steering device of therudders and synchronize these with the thrust the marine vessel issubjected to via the first and the second propulsion units and the bowthruster. The step removes the need for individual steering of therudders by the driver when performing the sideway displacement.

The first and the second propulsion units may each have a forward, areverse and optionally a neutral gear. The gears may be selectedautomatically in dependence of a driver operating the single driverinterface. This provides a combined control of the transmissions andassociate that control with the rudder control via the single driverinterface.

The method may be performed at a first level of thrust, and subsequentlyat a second level of thrust. The first level of thrust is preferably alow speed displacement and the second level of thrust is preferably ahigh speed displacement. The terminology low speed and high speed asused herein is meant to be understood in relative terms during a sidewaydisplacement. A low speed sideway displacement may be a speed of 0.5knots, and a high speed sideway displacement may be a speed of 1.5knots. The speed may be measured as the speed over ground at zerocurrents and zero wind.

The sideway displacement may be substantially a parallel sidewaydisplacement, i.e. a sway motion, or a parallel sideway displacement,i.e. a pure sway motion. It has been found that the step isadvantageously performed as a straight starboard or straight port swaymotion. Additional displacement maneuvers may be performed in order toset the rudder angles. Just as a matter of example, the method maycomprise a low speed and a high speed displacement of a selected ofnumber maneuvers to set the relation between the rudder angles and thetotal thrust.

At the first level of thrust, the rudder angles of the first and thesecond rudders may be set to substantially 0°, or to 0°. Setting therudder angles to substantially 0°, or to 0° provide a maximum sternresistance during the sideway displacement enables a balancing betweenthe maximum stern resistance and the bow thruster. This is specificallyadvantageous when the first level of thrust corresponds to a low speeddisplacement of the marine vessel.

At the second level of thrust, the rudder angles of the first and thesecond rudders may be set substantially parallel, or parallel, and at arudder angle of 5-20° port or starboard.

Suitable rudder angles may vary dependent on the hull, the rudder sizeand shape. Suitable rudder angles may preferably be 6-13° port orstarboard such as 6°, 7°, 8°, 9°, 10°, 11°, 12° or 13°. This isspecifically advantageous when the second level of thrust corresponds toa high speed displacement of the marine vessel. The second calibrationstep may be high speed displacement and the sideway displacement may besubstantially a parallel sideway displacement, or a parallel sidewaydisplacement.

At the second level of thrust, the bow thruster may be set to at least75% of maximum thrust. It is advantageous to set a high level of bowthrust as this brings the conditions closer to the extremes. Othersuitable levels are at least 80, 85, or 90% of maximum thrust. It ishowever advantageous not to exceed 90% of maximum thrust as it may bedesirable to enable the driver with a degree of manual compensation.Just as a matter of example, a driver performs a sideway displacement ofthe marine vessel in accordance with the method disclosed herein and themarine vessel is subjected to a cast wind, or a temporarily currentchange, the driver may want to manually balance the sideway displacementusing the single driver interface. This may be achieved by not using themaximum thrust available but setting a relatively high level of thrustsuch as 75-90% of maximum thrust as second level of thrust.

The first and the second rudders may be operated to be parallel withrespect to each other during the sideway displacement. It may be notedhowever that small deviations may be permitted. The method may forexample include a step by which one of the rudders is temporarilyslightly offset with respect to the other rudder. Just as a matter ofexample, the offset may be up to 5° port or starboard, but not more. Anoffset such as this may be used to compensate for a temporary loss ofpower in one of the propulsion units during displacement for example. Ina similar manner, the method may include a step by which one of therudders is permanently slightly offset with respect to the other rudder.Such offset may be done to compensate for the marine vesselshydrodynamics for example. It should be noted that a permanent offsetmay be changed, or updated, continuously. Just as matter of example, apermanent offset may be updated once a month in order to compensate forfouling of the hull, the rudders, or the propellers.

According to an aspect, the total thrust may be provided by a thrust ofthe bow thruster and a forward thrust of the first propulsion unit and arearward thrust of the second propulsion unit. Optionally a rearwardthrust of the first propulsion unit and a forward thrust of the secondpropulsion unit. The option of being able to control both rudderstogether with all the thrusters in a combined manner gives a smoothoperation.

The first and the second propulsion units may have fixed thrustdirections. The fixed thrust directions may be forward and reverse, forinstance forward and reverse only. By the term fixed thrust direction asused herein is meant that the propulsion units are non-steerable. Thepropulsion units may be provided with inboard shafts having nonsteerable propellers. The marine vessel may have an inboard shaft lineinstallation comprising a first and a second inboard shaft associatedwith the first and the second propulsion units respectively for example.The pitch angle of the propellers and/or the rotational speed mayhowever still be manipulated even if the thrust directions are fixed.

The sideway displacement may be a sideway docking displacement. Themethod is specifically useful for docking maneuvers. As the methodprovide for smooth operation and a more balanced operation of the marinevessel, the method is highly useful for docking maneuvers or forcalibrating the rudder angles for docking maneuvers.

The single driver interface may be a joystick, touch pad or the like. Bythe term single driver interface is herein meant that at least steeringand throttle can be operated via one single device, preferably also thetransmission of the propulsion units, i.e. switching between forward,reverse and neutral gear.

As mentioned, the single driver interface may be a joystick. The changeof rudder angles of the first and the second rudders are preferablyassociated with the rotation and/or tilting of the joystick.

It has been found that the method for performing a sideway displacementof the marine vessel method may advantageously be used a calibrationmethod. The method may be used to calibrate rudder angles of the firstand the second rudders as a function of the total thrust. The methodenables the settings of the rudders during preferably at least twodistinct maneuvers between which a relationship may be derived betweenthe suitable rudder angles and a proper balance during the sidewaydisplacement of the marine vessel. The rudder angles at a first level ofthrust, and the rudder angles at a second level of thrust may be storedon a storage device. Via an algorithm of a steering and throttle controlmodule, the rudder angles may thereafter be set as a function based onthe stored values, preferably a linear function.

According to an aspect, the method may comprise the step of controllingand/or displacing the first and the second rudders to set the rudderangles. It is advantageous to control both the rudders using the singledriver interface; this provides a smooth displacement which also enablesboth the rudders to be steered during displacement. The rudders may becontrolled and/or displaced substantially in parallel together. The setrudder angles of the first and the second rudders are preferably morethan 0°.

According to an aspect, the disclosure also relates to a computerprogram comprising program code means for performing any one of thesteps when the program is run on a computer, and a computer readablemedium carrying a computer program comprising program code means forperforming any one of the steps when the program product is run on acomputer.

According to an aspect, the objects are also at least partly achieved bya marine vessel single driver interface steering arrangement forimplementing the method disclosed herein. The marine vessel singledriver interface steering arrangement comprising at least a first and asecond propulsion unit, a first and a second rudder respectivelyassociated with the first and the second propulsion units, and a bowthruster. The marine vessel single driver interface steering arrangementis configured to enable a sideway displacement of a marine vessel viathe single driver interface by operating the first and the secondpropulsion units and the bow thruster so as to provide a total thrust,and optionally setting the rudder angles of the first and the secondrudders as a function of the total thrust, to thereby steer thedisplacement of the marine vessel during the sideway displacement.

The first and the second propulsion units may have fixed thrustdirections. As mentioned above, the first and the second propulsionunits are preferably stern propulsion units. The first and the secondrudders are preferably positioned so that they intersect with the thrustdirection formed by the first and the second propulsion unitrespectively, i.e. the thrust from the first propulsion unit should bedirected towards the first rudder when the first propulsion is inforward gear. Likewise, the thrust from the second propulsion unitshould be directed towards the second rudder when the second propulsionunit is in forward gear.

The marine vessel may comprise an inboard shaft line installationcomprising a first and a second inboard shaft associated with the firstand the second propulsion units respectively. The rudder angles of thefirst and the second rudders may be set as a function of the totalthrust.

The marine vessel single driver interface steering arrangement maycomprise a memory module for storing data relating to the rudder angles.The data may be used to calibrate the marine vessel single driverinterface steering arrangement so that the angle of the rudders can beoperated via the single driver interface. The marine vessel singledriver interface steering arrangement can be calibrated using thedisclosed method.

Further advantages and advantageous features of the invention aredisclosed in the following description and in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

With reference to the appended drawings, below follows a more detaileddescription of embodiments of the invention cited as examples.

In the drawings:

FIG. 1 shows a schematic overview of a marine vessel having a steeringand propulsion arrangement.

FIG. 2-9 show the marine vessel performing different maneuvers whileillustrating thrust directions and joystick control.

FIG. 10-12 show schematic block diagrams illustrating the method forperforming a sideway displacement of a marine vessel.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

FIG. 1 shows a schematic overview of a marine vessel 10 and a steeringand propulsion arrangement 20 for operating the marine vessel 10. Thesteering and propulsion arrangement 20 comprises a helm station 21. Thehelm station 21 is provided with a joystick 22, a steering wheel 23,throttles 24 and instrument and navigational data interface 25. Thejoystick 22 represents a single driver interface. A single driverinterface enables a driver of the marine vessel to operate the steeringand the propulsion of the marine vessel in a desired direction usingonly one single driver interface. A joystick is an example of suchsingle driver interface. Another example is a touch pad interfacerepresenting a virtual joystick.

A rudder actuator 30 such as an electrical rudder actuator isoperatively connected to a first and a second rudder 31, 32 andcontrolled via the joystick 22 and/or the steering wheel 23. It shouldbe noted that the rudder actuator 30 could one or more individual rudderactuators. Each rudder 31, 32 could be provided with an individualrudder actuator for example, or use one common rudder actuator. Thefirst and the second rudders 31, 32 are also referred to as port andstarboard rudder 31, 32. The rudder actuator 30 governs the positioningof the first and the second rudder 31, 32 as a response to an inputsignal to the electrical rudder actuator. A first and a secondpropulsion unit 26, 27 is arranged in working cooperation with a firstand a second propeller (not shown). The first and the second propulsionunits 26, 27 are also referred to as port propulsion unit 26 andstarboard propulsion unit 27. The first and the second propulsion unitsare stern propulsion units. A steering and thruster control module 35operates as an integrating hub between the helm station 21 and therudders and the first and the second propulsion units 26, 27. Anavigation unit 36 such as an electronic compass and GPS device providesnavigational data. The steering and propulsion arrangement 20 furthercomprises a bow thruster 37 positioned in the bow of the marine vessel10. A bow thruster is located forward of the midship of the marinevessel, preferably in the proximity of the bow. The first and the secondrudders 31, 32 are preferably positioned so that they intersect with thethrust direction formed by the first and the second propulsion unit 26,27 respectively, i.e. the thrust from the first propulsion unit 26should be directed towards the first rudder 31 when the first propulsionis in forward gear. Likewise, the thrust from the second propulsion unit27 should be directed towards the second rudder 32 when the secondpropulsion unit 27 is in forward gear.

A method according to the present invention will use the propulsionunits, gears and thruster together with the rudders to balance themarine vessel during displacement in an efficient manner. The methodoffers the possibility to maneuver the marine vessel sideways and intransversal directions without the need for stern thrusters. The methodmay thus be implemented on marine vessels having non steerablepropellers, i.e. fixed stern drives, i.e. stern drives which cannot berotated. It is of course possible to apply the disclosed method onmarine vessels having rotatable stern drives. That may be useful if therotatable stern drives are temporarily fixed or blocked. The method willbe disclosed in greater detail with reference to the figures below. Thepropulsion units 26, 27 may be combustion engines such as dieselengines, or electrical motors connected to batteries, fuel cells or thelike, or hybrid motors. The propulsion units may impart the thrust viapropellers and/or jet propulsion.

FIG. 2 shows the marine vessel 10 during a sideway displacementmaneuver. FIG. 2 shows the marine vessel 10 illustrated before and afterthe displacement, and the displacement direction F1 between the endpositions. FIG. 2 also show the joystick 22, representing the singledriver interface, and how the joystick 22 is operated to maneuver themarine vessel 10. The joystick 22 comprises a lever 22′. Further shownis a schematic illustration of the marine vessel 10 with a view fromabove and with the thrust forces imparted by the first and the secondpropulsion units 26, 27 (not shown) via a first and a second propeller28, 29 respectively, and the bow thruster 37.

By operating the first and said second propulsion units 26, 27 and thebow thruster 37, a total thrust is provided. The total thrust is thethrust resulting from the individual thrusts which act on the marinevessel 10. The individual thrusts are illustrated by the force linesoriginating from the port and the starboard propellers 28, 29 and thebow thruster 37. The rudder angles α will further be set as a functionof the total thrust, to steer the displacement of the marine vesselduring a displacement such as during a sideway displacement.

The rudder angle is set with respect to the longitudinal center line Lof the marine vessel, and is expressed as the angle of the rudder whenview from above and the longitudinal axis L as indicated in FIG. 2. Therudder angle α is expressed as a port angle and a starboard anglestarting from zero degrees when the rudder is parallel with thelongitudinal center line L of the marine vessel. FIG. 2 shows the firstand the second rudders 31, 32 being tilted with 10 degrees port angle,hence α1=10° port and α2=10° port. The position of the first and thesecond rudders 31, 32 correspond to the joystick side position toincrease/decrease side thrust, and can optionally be centered when thejoystick is released.

With reference to FIG. 2, the joystick 22 is operated by a driver bytilting the joystick 22 to starboard commanding the marine vessel 10 tobe displaced sideways as indicated by the arrow F1. The bow thruster 37is propelling the bow of the marine vessel 10 in a starboard directionand thus imparting a thrust illustrated by the force lines at port. Theport propeller 28 imparts a forward thrust and the starboard propeller29 imparts a rearward thrust. The first propulsion unit 26 is thus inreverse gear and the second propulsion unit 27 is in forward gear. Thefirst and the second rudders 31, 32 are set as a function of the totalthrust to steer the displacement, i.e. to balance the displacement. Thefirst and the second rudders 31, 32 each have a rudder angle α1, α2 withrespect to a longitudinal axis L of the marine vessel 10. The throttlewill correspond to the current joystick starboard side position, idlewhen joystick is released as the joystick will return to neutralposition. In several, embodiments disclosed herein, it may be preferredthat the magnitude of the thrust produced by each one of the first andthe second propulsion units and the bow thruster is such that thethrusts together produce a yaw moment that is lower than a predeterminedvalue, preferably close to zero, and also Fx=0.

The following figures show the marine vessel 10 shown in FIG. 2, thesame features having the same reference. FIG. 3 shows the marine vessel10 during a sideway displacement in a port direction. The throttleresponse corresponds to current joystick port side position. Thethrottle is idle when the joystick is released. The gear of the portpropulsion unit is in reverse and the gear of the starboard propulsionunit is in reverse. The bow thruster 37 thrusts at starboard when thejoystick is in any port side position. No thrust is provided when thejoystick is released. The rudder angle α1, α2 of the first and thesecond rudders 31, 32 are set to correspond to the port side position ofthe joystick to decrease/increase the side thrust, optionally centeredwhen the joystick is released.

FIG. 4 illustrates a sideway displacement to starboard with a rotationcompensation bow. The throttle response will correspond to the currentjoystick starboard side position and idle when the joystick is released.To perform the rotation compensation, the starboard propulsion unit willreduce the forward thrust e.g. by lowering the rotation speed of thepropellers. The gear of the port propulsion unit will be in reverse andstarboard propulsion unit in forward gear. Gear is switched to neutralwhen joystick 22 is released. The bow thruster 37 thrusts at port whenthe joystick is in any starboard position and cease to thrust when thejoystick is released. The rudder angle α1, α2 of the port and starboardrudders 31, 32 correspond to the joystick position to decrease/increasethe side thrust, and optionally center when the joystick is released.The rotation compensation bow is initiated by rotating the joystick 22as shown by the arrow. When performing the rotation compensation bow,the rudder angles α1, α2 will decrease to thereby lower the sternthrust. Hence the joystick 22 is here used to initially set the rudderangles α1, α2 and subsequently to adjust the rudder angles α1, α2 toperform the rotation compensation bow maneuver.

FIG. 5 illustrates a sideway displacement to starboard with a rotationcompensation stern. The throttle response corresponds to the currentjoystick starboard side position, idle when the joystick is released.When performing the rotation compensation stern, the port propulsionunit will increase its revolutions to increase thrust from the portpropulsion unit. The gear of the port propulsion unit is in reverse andthe gear of the starboard propulsion unit is in forward. Gears areswitched to neutral when the joystick is released.

The bow thruster 37 thrusts at port when the joystick is in anystarboard position and cease to thrust when the joystick is released.The position of the rudders 31, 32, i.e. the rudder angles α1, α2, willinitially correspond to the joystick starboard side position todecrease/increase the side thrust, and optionally center when thejoystick 22 is released. When performing the rotation compensation sternmaneuver, the bow thruster 37 will decrease thrust and the rudder angleα1, α2 of the first and the second rudder 31, 32 will increase toincrease the stern thrust.

During the different displacements maneuvers illustrated in FIGS. 2-5,the rudder angle α1, α2 of the first and the second rudders 31, 32 areset as a function of the total thrust to steer the marine vessel 10during the displacement, i.e. to decrease and/or increase the stern orside thrust. The displacement of the marine vessel 10 is operated viatilting the joystick 22, and as such, the rudder angles α1, α2 can thusbe set as a function of the tilted position of the joystick. Asdisclosed above, the different positions of the joystick correspond todifferent thrust settings and can thus be correlated to set the angleα1, α2 of the first and the second rudders 31, 32.

FIGS. 6 and 7 illustrate the marine vessel 10 during a clock-wise andcounter clock-wise rotation but in comparison with the displacementdescribed above, these maneuvers rely strictly on a rotation of thejoystick 22. With reference to FIGS. 6-7, the throttle response willcorrespond to the current joystick rotation rate, or angle of rotation.The throttle is idle when the joystick 22 is released. The starboardpropulsion unit is in forward gear and the port side propulsion unit isin reverse gear and vice versa depending on the desired rotation of themarine vessel. When the joystick 22 is released the gears are set toneutral. The bow thruster 37 is idle as the bow thruster is not used forrotation. The first and the second rudders 31, 32 are set to an anglecorresponding to the joystick rotation rate and/or to the angle ofrotation of the joystick. The rudders are optionally centered when thejoystick 22 is released.

FIG. 8 illustrate the marine vessel 10 performing a forward sidemovement starboard and FIG. 9 a forward side movement port. The throttleresponse corresponds to the joystick position and forward side movement.The throttle is idle when the joystick is released. The gear of the portpropulsion unit is in reverse and the gear of the starboard propulsionunit is in forward gear. The bow thruster 37 thrust at port when thejoystick is off centre to starboard and no thrust when the joystick isreleased. The first and the second rudders 31, 32 may be used by settingdifferent angles to counteract the marine vessels 10 rotation whenmoving forward sideways. The first and the second rudders 31, 32 may becentered when the joystick is released. In the shown embodiment, therudders 31, 32 may be steered via rotation of the joystick, but isinitially set at an angle as a function of the total thrust imparted onthe marine vessel when tilting of the joystick. The same principle maybe used to displace the marine vessel in a backward side movement portand starboard.

FIG. 10 shows a schematic block diagram illustrating a non-limitingembodiment of the method for performing a sideway displacement of amarine vessel. At step 100 A driver operates the single driverinterface, in this case a joystick, to move the marine vessel sidewaysstraight to starboard. At 110 The steering and thruster control modulereceives the input signal carrying the displacement command via thesingle driver interface, in this case the joystick. When the steeringand thruster control module has received the command signal, thesteering and thruster control module actuates the first and the secondpropulsion units, i.e. the port and the starboard propulsion units, thebow thruster and the port and the starboard rudder in accordance withthe received command.

At steps 120, 130 the port and starboard propulsion units are put ingear in accordance with the given command. In this case, the portpropulsion unit 120 is put in reverse gear Rse and the starboardpropulsion unit 130 is put in forward gear Frwd. The throttle is set toa corresponding value to the inclination of the joystick, i.e. withrespect to the indicated value by the driver using the single driverinterface.

At 140 The bow thruster thrusts at port, indicated by the reference Portin FIG. 10, thus pushing the bow in a starboard direction. The amount ofthrust is set to a corresponding value to the inclination of thejoystick, i.e. with respect to the indicated value by the driver usingthe single driver interface.

At 150 The rudder angle of the port and starboard rudders are set by arudder actuator and in accordance with a preset value as a function onthe total thrust. In this case, the rudder angle value is retrieved froma memory module 151, e.g. the steering and thrust control module. As anoption, the rudder angle may be set to a corresponding value to theinclination of the joystick, i.e. with respect to the indicated value bythe driver using the single driver interface. At step 152 the port andstarboard rudders are operated in parallel to the set rudder angles.

200 indicate that a number of sensors are continuously detecting andforwarding measured values to the steering and thrust control module.The sensors may be one or more, but are advantageously sensors such asrudder angle sensors, fuel sensors, pressure sensors, temperaturesensors and the like.

The method may be applied as a calibration method to provide suitablerudder angles as a function of a total thrust. More specifically themethod may be a calibration method for calibrating the rudder angles ofthe first and the second rudders with the total thrust using a sidewaydisplacement. It has been found to be advantageous to apply thedisclosed method as a calibration method as it may set unique parametersfor each marine vessel to provide a proper balance between the bowthruster(s), the rudders and the propulsion unit(s). Suitable parametersmay be; rudder angles, amount of thrust such as propulsion unit throttlelevel, and gear, such as the propulsion units being in forward orreverse gear.

For the purpose of describing the calibration method in greater detail,reference will be made to FIG. 2. The marine vessel 10 in FIG. 2 is asillustrated operated to move in a straight starboard direction, but aswill also be understood is that movement in straight port direction mayalso be used as shown in FIG. 3. The displacement may be used to providea calibration method preferably from one or more selected parametersduring such displacement. Such selected parameters may be stored in astorage module and subsequently be used for setting e.g. rudder anglesor other devices.

The calibration method may be performed at a first level of thrust, andsubsequently at a second level of thrust. Just as a matter of example,the calibration method may comprise displacing the marine vessel 10 at afirst and a second speed in a straight port or starboard direction.

With reference to FIG. 2, the first calibration step may thus be todisplace the marine vessel in a first direction at a first speed. Thefirst speed is preferably relatively low, and may thus form to set theparameters for a low speed marine vessel movement. The throttle is thusset at low. The bow thruster thrust at port, the port propulsion unitput in reverse gear, the starboard propulsion unit put in forward gearand the port and starboard rudder angles α1, α2 are set to 0°. In thispart, the balance between the thrust provided by the port and starboardpropulsion units and the rudder angles α1, α2 set to 0° forming thestern thrust. The bow thrust is set to match the provided stern thrustby controlling the bow thrust proportionally from about 5-100%, butsuitably between 5-20%, when the marine vessel 10 side movement isconsidered true parallel, as indicated by the arrow F1 in FIG. 2. Therudder angles and thrust levels are stored in a memory module.

During a second calibration step, the marine vessel 10 is displaced inthe same direction as in the first calibration step but at a secondspeed, the second speed being different from the first speed, preferablyhigher. The second speed is preferably relatively high, and may thusform to set the parameters for a high speed marine vessel movement. Thebow thruster 37 thrust at port, the port propulsion unit is put inreverse gear, the starboard propulsion unit is put in forward gear andthe port and starboard rudder angles α1, α2 are set to 5-20° port suchas approximately 10° port. The bow thrust is set to a fixed value of 90%of maximum but other fixed values may be applied such as 75% or higherof the maximum thrust. The thrust provided by the port and starboardpropulsion units are balanced until the side movement of the marinevessel 10 is considered true parallel as indicated by the arrow F1 inFIG. 2. This operation will decide and set the maximum fast vesselmaneuver.

To determine if the side movement is considered true parallel anavigation unit may be used, such as GPS. Optical measurement mayfurther be performed.

The two calibration steps, represented by repeating the method twice,set the parameters for a fast and a slow displacement of the marinevessel, and represent extreme values, i.e. two ends of a scale. Therudder angles may be set linearly between these two ends.

When the two calibration steps are performed and implemented the driveronly need to focus on compensating for wind and current if needed. Ifthe maximum bow thrust is set to 90% of the maximum available thrust, aspare force of +10% in the thrust is available for the driver in orderto provide the possibility for the driver to adjust the balance betweenstern and bow in real-time. The driver may further be permitted toreduce the bow thrust all the way down to 0%, to adjust for wind andcurrents. The adjustment is preferably done by rotating or tilting thejoystick to compensate for wind and current during a sidewaydisplacement maneuver of the marine vessel 10. In general terms, themethod may include the option to perform a rudder angle compensationusing the single driver interface. The rudder angle compensation may be±5°, or preferably ±4°, more preferably ±3° depending on the hull,propellers and rudder size and shape. The joystick function is by thismapped between the two calibration points, and preferably linearlymapped between the two calibration points, i.e. the low speed maneuverand the high speed maneuver. This enables a driver to control the marinevessel 10 step less within the low speed and the high speed range (minto max) as desired.

The calibration method may be a powertrain calibration method and usedin a marine vessel. The calibration method may comprise the steps:

-   -   Performing a first sideway displacement in which a first        propulsion unit is in forward gear, and a second propulsion unit        is in reverse gear.    -   The bow thruster and the first and the second rudders are        balanced in order to set a low speed straight sideway, i.e.        parallel, marine vessel displacement.    -   A low speed parallel marine vessel displacement may be defined        by that the bow thrust is not exceeding 10% of the maximum        thrust, such as the bow thruster is set to 1, 2, 3, 4, 5, 6, 7,        8, 9 or 10% of the maximum thrust depending on the hull,        propellers and bow thruster size.

Performing a second sideway displacement in which the first propulsionunit is in forward gear, and the second propulsion unit is in reversegear. The bow thruster and the first and the second rudders are balancedin order to set a high speed straight sideway, i.e. parallel, marinevessel displacement.

The bow thruster, the port and starboard propulsion units and the rudderangles of the first and the second rudder may be balanced with respectto each other in order to provide a straight sideway displacement of themarine vessel. In the first calibration step for example, the rudderangle of the first and the second rudder may be set to 0°, while in thesecond calibration step, the rudder angle of the first and the secondrudder may be set to 5-20° port or starboard dependent on whichdirection the sideway displacement is directed.

Further, at a high speed marine vessel sideway displacement, the bowthrust power may be set to at least 75% of maximum, or 80, 85, 90% ofmaximum, i.e. full bow thrust power, and subsequently finding a balancebetween forward and reverse thrust of the port and starboard propulsionunits. The bow thrust should however not exceed 90% of maximum thrust.

The first and the second calibration steps may be performed in reversedorder of course, i.e. a high speed sideway displacement of the marinevessel may be performed before the low speed sideway displacement.Optionally the first two calibration steps may be followed by a mappingbetween calibrated parameters of the low speed sideway displacement andthe high speed sideway displacement. The mapping may be a linearfunction or a non-linear function.

FIG. 11 shows a schematic block diagram of an embodiment of thecalibration method to calibrate the rudder angles with respect to thetotal thrust. For the purpose of describing the calibration method, thesideway displacement shown in FIG. 2 will be used.

At step 101 in FIG. 11 a driver initiates the calibration command viathe helm station of the marine vessel. The calibration command may beinitiated via the single driver interface, or via an instrument panel atthe helm station. In accordance with the calibration command, the driveris invited to displace the marine vessel in a straight starboarddirection using the single driver interface. A signal may be issued toalert the driver that the calibration command has been initiated andthat the marine vessel is ready to perform the calibration method.

At 110 in FIG. 11 and in accordance with the low speed calibrationcommand for a starboard sideway displacement, the port propulsion unitis put in reverse gear and the starboard propulsion unit is put inforward gear at a set revs/min. The bow thruster is open for operationfor the driver. The first and the second rudders are set to 0°. In thiscase a low speed calibration command was issued first. As an option, ahigh speed calibration command may initially be issued. The throttle ismaintained below a threshold value.

At 140 in FIG. 11 the bow thruster is operable by the driver so as tobalance the marine vessel so as to get a straight starboarddisplacement. 141 if a straight starboard displacement is not achieved,a signal will alert the driver to adjust the bow thruster until astraight starboard displacement is achieved. The determination may beperformed by a navigation unit e.g. via GPS data, or opticalmeasurements.

At 151 in FIG. 11 the data from the first and the second propulsionunits, the bow thruster, the thrust level and the rudders are stored ata storage module 151 and available to the steering and throttle controlmodule for later operations.

FIG. 12 shows a schematic block diagram of an embodiment of thecalibration method to calibrate the rudder angles with respect to thetotal thrust. For the purpose of describing the calibration method, thesideway displacement shown in FIG. 2 will be used. Following the lowspeed displacement, a high speed displacement command is issued.

At step 110 in FIG. 12 and in accordance with the high speed calibrationcommand for a starboard sideway displacement, the port propulsion unitis put in reverse gear and the starboard propulsion unit is put inforward gear. The bow thruster is set to 75% of maximum thrust. Thefirst and the second rudders are set at a rudder angle of 5-20° port inthis case about 8° port.

At steps 120/130 in FIG. 12 the first and the second propulsion unitsare operable by the driver so as to balance the marine vessel so as toget a straight starboard displacement. At step 125 if a straightstarboard displacement is not achieved, a signal will alert the driverto adjust the bow thruster until a straight starboard displacement isachieved. The determination may be performed by a navigation unit e.g.via GPS data, or optical measurements.

At 151 in FIG. 12 the data from the first and the second propulsionunits, the bow thruster, the thrust level and the rudders are stored ata storage module 151 and available to the steering and throttle controlmodule for later operations.

The above described method may be performed any number of times such asone, two or three times or more.

It is to be understood that the present invention is not limited to theembodiments described above and illustrated in the drawings; rather, theskilled person will recognize that many changes and modifications may bemade within the scope of the appended claims.

The invention claimed is:
 1. A method for performing a sidewaydisplacement of a marine vessel, said marine vessel comprising a firstand a second propulsion unit, a first and a second rudder respectivelyassociated with said first and said second propulsion units, and a bowthruster, said first and said second propulsion units, said first andsaid second rudders and said bow thruster being operable via a singledriver interface, said method comprises via said single driverinterface; operating said first and said second propulsion units andsaid bow thruster so as to provide a total thrust and setting rudderangles of said first and said second rudders, to thereby steer thesideway displacement of said marine vessel during said sidewaydisplacement whereby said method is performed at a first level ofthrust, and at a second level of thrust, whereby said first level ofthrust is a low speed displacement and said second level of thrust is ahigh speed displacement, whereby at said first level of thrust, saidrudder angles of said first and said second rudders are set to 0°,whereby at said second level of thrust, said rudder angles of said firstand said second rudders are set parallel, and to a rudder angle of 5-20°port or starboard, whereby at said second level of thrust, said bowthruster is set to at least 75% of its maximum thrust.
 2. The methodaccording to claim 1, whereby said first and said second propulsionunits each has a forward and a reverse gear, whereby said gears can beselected automatically in dependence of a driver operating said singledriver interface.
 3. The method according to claim 1, whereby settingsaid rudder angles is a function between said rudder angles and thelevel of thrust of at least said bow thruster.
 4. The method accordingto claim 1, whereby said method comprises the step of setting the rudderangles of said first and said second rudders as a function of said totalthrust.
 5. The method according to claim 3, whereby said function is amapped function such as a linear function or a non-linear function. 6.The method according to claim 1, whereby said sideway displacement issubstantially a parallel sideway displacement.
 7. The method accordingto claim 1, whereby said first and said second rudders are operated tobe parallel with respect to each other during said sideway displacement.8. The method according to claim 1, whereby said total thrust isprovided by; a thrust of said bow thruster and; a forward thrust of saidfirst propulsion unit and a rearward thrust of said second propulsionunit or; a rearward thrust of said first propulsion unit and a forwardthrust of said second propulsion unit.
 9. The method according to claim1, whereby said first and said second propulsion units have fixed thrustdirections.
 10. The method according to claim 1, whereby said sidewaydisplacement is a sideway docking displacement.
 11. The method accordingto claim 1, whereby said marine vessel has an inboard shaft lineinstallation comprising a first and a second inboard shaft associatedwith said first and said second propulsion units respectively.
 12. Themethod according to claim 1, whereby said single driver interface is ajoystick, touch pad or the like.
 13. The method according to claim 12,whereby said single driver interface is a joystick, and whereby a changeof rudder angles of said first and said second rudders are associatedwith the rotation and/or tilting of said joystick.
 14. The methodaccording to claim 1, whereby said first and said second propulsionunits are stern propulsion units.
 15. The method according to claim 1,whereby said method is used to calibrate said rudder angles of saidfirst and said second rudders with said total thrust, preferably bydetermining rudder angles as a function of said total thrust.
 16. Themethod according to claim 15, whereby said method comprising the stepof; storing the rudder angles at a first level of thrust, and storingthe rudder angles at a second level of thrust.
 17. The method accordingto claim 1, whereby said method comprises the step of; controllingand/or displacing said first and said second rudders to set said rudderangles.
 18. A non-transitory computer readable medium carrying acomputer program comprising program code, the program code performing amethod for performing a sideway displacement of a marine vessel, saidmarine vessel comprising a first and a second propulsion unit, a firstand a second rudder respectively associated with said first and saidsecond propulsion units, and a bow thruster, said first and said secondpropulsion units, said first and said second rudders and said bowthruster being operable via a single driver interface, said methodcomprises via said single driver interface, when said program product isrun on a computer: operating said first and said second propulsion unitsand said bow thruster so as to provide a total thrust and setting rudderangles of said first and said second rudders, to thereby steer thesideway displacement of said marine vessel during said sidewaydisplacement whereby said method is performed at a first level ofthrust, and at a second level of thrust, whereby said first level ofthrust is a low speed displacement and said second level of thrust is ahigh speed displacement, whereby at said first level of thrust, saidrudder angles of said first and said second rudders are set to 0°,whereby at said second level of thrust, said rudder angles of said firstand said second rudders are set parallel and to a rudder angle of 5-20°port or starboard, whereby at said second level of thrust, said bowthruster is set to at least 75% of its maximum thrust.
 19. A marinevessel single driver interface steering arrangement, said marine vesselsingle driver interface steering arrangement comprising at least a firstand a second propulsion unit, a first and a second rudder respectivelyassociated with said first and said second propulsion units, and a bowthruster, where said marine vessel single driver steering arrangement isconfigured to enable a sideway displacement of a marine vessel via saidsingle driver interface by; operating said first and said secondpropulsion units and said bow thruster so as to provide a total thrustand; setting rudder angles of said first and said second rudders tothereby steer the sideway displacement of said marine vessel during saidsideway displacement, wherein said marine vessel single driver steeringarrangement is configured to perform at a first level of thrust, and ata second level of thrust, whereby said first level of thrust is a lowspeed displacement and said second level of thrust is a high speeddisplacement, whereby at said first level of thrust, said rudder anglesof said first and said second rudders are set to 0°, whereby at saidsecond level of thrust, said rudder angles of said first and said secondrudders are set parallel, and to a rudder angle of 5-20° port orstarboard, whereby at said second level of thrust, said bow thruster isset to at least 75% of its maximum thrust.
 20. The marine vessel singledriver interface steering arrangement according to claim 19, whereinsaid first and said second propulsion units have fixed thrustdirections.
 21. The marine vessel single driver interface steeringarrangement according to claim 19, wherein said marine vessel comprisesan inboard shaft line installation comprising a first and a secondinboard shaft associated with the first and the second propulsion unitsrespectively.
 22. The marine vessel single driver interface steeringarrangement according to claim 19, wherein said rudder angles of saidfirst and said second rudders are set as a function of said totalthrust.
 23. The marine vessel single driver interface steeringarrangement according to claim 19, wherein said marine vessel singledriver interface steering arrangement comprises a memory module forstoring data relating to said rudder angles.